M20b27 oil leak.

[Captainslow]

Hey guys! So ive noticed that after i park my 528e i can see there are drops of oil beneath it. The leak isnt huge but its concerning. So Today while i was under the car i noticed the leak starts at the top of the cylinder head and has pretty much everything on that side all the way to the bottom covered in oil. My question is what could it be? http://m.imgur.com/voFBkko http://m.imgur.com/auK41lZ

[demetk]

Might be a headgasket leak. Mine is leaking in the same place.

[Captainslow]

Might be a headgasket leak. Mine is leaking in the same place.

How is this for diy?

[tig]

Mine leaks there too. I'm going to replace the engine because I hate leaks so much.

[dsmith]

Might be a headgasket leak. Mine is leaking in the same place.

How is this for diy?

The only difficult part is removing manifold bolts. You could leave the manifold and remove the downpipe nuts instead. Parts are whatever rubber parts and gaskets/seals have not been replaced, head bolts, coolant, oil, timing belt kit, water pump and whatever you break.

Pretty easy over a weekend, if you aren't touching the head. Clean, remove and clean everything day 1. Reassemble day 2.

[Captainslow]

Might be a headgasket leak. Mine is leaking in the same place.

How is this for diy?

The only difficult part is removing manifold bolts. You could leave the manifold and remove the downpipe nuts instead. Parts are whatever rubber parts and gaskets/seals have not been replaced, head bolts, coolant, oil, timing belt kit, water pump and whatever you break.

Pretty easy over a weekend, if you aren't touching the head. Clean, remove and clean everything day 1. Reassemble day 2.

Thank you!

[demetk]

But before you accept our conclusions make sure it's not your valve cover that's leaking.

[SeaWolf]

But before you accept our conclusions make sure it's not your valve cover that's leaking.

or cam seal, they can make a mess everywhere.

[JohnH]

or cam seal, they can make a mess everywhere.

Thats where I'de put my money first & its an easy fix.

[duggi]

A few things...

(1) All m20s with >100k miles on them leak oil, it's just a thing they do. Yes, fastidious replacement of seals at factory recommended intervals can significantly reduce the leaks, but overall preventing them for any length of time is wishful thinking.

(2) You stated in your post that the leak looked like it was coming from the top of the head, but in your images it looks like the head itself is clean and shiny and the leaking is happening at the bottom of the head, where it mates to the block - if this is actually the case, it would indicate a head-gasket issue. Do double-check though, because if the leak is coming from the top of the head, your likely culprit is the valve cover gasket, which is an easy replacement that shouldn't take more than 5-10 minutes.

(3) If it is in fact the head gasket, a weekend is doable for someone who has experience and all the right tools and a well-setup place to work - I've done three head gaskets now and would still always plan on two weekends, just so I can take my time and do it right. There are also a number of components that have to come off to remove the head, so do some research on the forum to see what else you'll need - from the top of my head: timing belt (and water pump since you're in there), intake manifold gaskets, exhaust manifold gaskets, valve cover gasket...

[Captainslow]

A few things...

(1) All m20s with >100k miles on them leak oil, it's just a thing they do. Yes, fastidious replacement of seals at factory recommended intervals can significantly reduce the leaks, but overall preventing them for any length of time is wishful thinking.

(2) You stated in your post that the leak looked like it was coming from the top of the head, but in your images it looks like the head itself is clean and shiny and the leaking is happening at the bottom of the head, where it mates to the block - if this is actually the case, it would indicate a head-gasket issue. Do double-check though, because if the leak is coming from the top of the head, your likely culprit is the valve cover gasket, which is an easy replacement that shouldn't take more than 5-10 minutes.

(3) If it is in fact the head gasket, a weekend is doable for someone who has experience and all the right tools and a well-setup place to work - I've done three head gaskets now and would still always plan on two weekends, just so I can take my time and do it right. There are also a number of components that have to come off to remove the head, so do some research on the forum to see what else you'll need - from the top of my head: timing belt (and water pump since you're in there), intake manifold gaskets, exhaust manifold gaskets, valve cover gasket...

It was definitely a mistake i did in fact mean the top of the block. Thank you! Really helpful info! Also i have zeeo experience, nada, zip. This is my first car and i want to do most diy as i can. Any good write ups on the head gasket seal or the cam seal? I cant find anything.

[dsmith]

... Also i have zeeo experience, nada, zip. This is my first car and i want to do most diy as i can. Any good write ups on the head gasket seal or the cam seal? I cant find anything.

You'll probably need that second weekend... Start with the e28 Bentley manual. These cars are fairly simple, but many items are tricky or difficult to remove/replace. The m20 intake can be interesting. Search for "oil return tube" to get a good idea on that part. Timing belt is easy, but it would be good if you had someone knowledgeable with you, since a screw up with ruin the motor.

These cars are 25 yrs old and all rubber and gaskets are going to be suspect. If you have the time (1 month) and money ($1k), it can be a good idea to go through the car all at once and be able to drive it for a couple of years without monthly failures.

[SeaWolf]

any good write ups on the head gasket seal or the cam seal? I cant find anything.

The cam seal is on the front of the camshaft on the cylinder head. You'll need to remove the cam timing pulley (only goes back on 1 way). The seal is secured in a soft alloy housing secured by 2 bolts, once the pulley is off remove the bolts, protection wrap the alloy seal housing in masking or gorilla tape and pull it out with a pair of channel locks - be careful when knocking out the old seal, the housing is very soft and you want to avoid any scratches or other damage to the seal surface. You'll need the seal and O ring.

The oil return pipe (aka bitch pipe) runs from the head to the crankcase, it's fitted with O rings and a retention spring - Give it a good clean so you can get a grip on it, put 2 good quality zip ties around the spring coils and pull tight with a flat screw driver & pliers relieving the spring pressure. Now you can wiggle it free. You'll need new O rings, a new spring is recommended if yours is rusted and crappy.

[Captainslow]

any good write ups on the head gasket seal or the cam seal? I cant find anything.

The cam seal is on the front of the camshaft on the cylinder head. You'll need to remove the cam timing pulley (only goes back on 1 way). The seal is secured in a soft alloy housing secured by 2 bolts, once the pulley is off remove the bolts, protection wrap the alloy seal housing in masking or gorilla tape and pull it out with a pair of channel locks - be careful when knocking out the old seal, the housing is very soft and you want to avoid any scratches or other damage to the seal surface. You'll need the seal and O ring.

The oil return pipe (aka bitch pipe) runs from the head to the crankcase, it's fitted with O rings and a retention spring - Give it a good clean so you can get a grip on it, put 2 good quality zip ties around the spring coils and pull tight with a flat screw driver & pliers relieving the spring pressure. Now you can wiggle it free. You'll need new O rings, a new spring is recommended if yours is rusted and crappy.

Thank you! Very detailed, appreciate it!

[turbodan]

You guys surely can't be suggesting this guy replace his head gasket as a starting point to fix an oil leak. That would be absurd.

Replace the valve cover gasket and rocker shaft cutout plugs, ensuring correct orientation and full seating of the plugs. If that doesn't do it inspect the cam seal and replace if needed. If you do replace the cam seal be extra careful to not damage the o ring on the seal carrier. You will likely damage it anyway, its easy to pinch.

The head gasket is the last thing that is going to leak oil. It is possible but very unlikely. Most people replace the valve cover gasket but screw up the rocker cutout plugs so it still leaks. Then they think it must be the head gasket because they incorrectly assume that it couldn't be the valve cover. Same goes for the cam seal.

[SeaWolf]

Nope, cam cover gasket and cam oil seal have been suggested by earlier posters.